I was the community manager of the Global CCS Institute for over three years. I have to admit, that I didn't know much about the technology when I started but as a pragmatic green nerd, the general concept appealed to me. The truth is that there are thousands of coal fired power plants around the world right now, and of course we should be capturing the CO2 from them - and yes, transitioning to a completely renewable energy future ASAFP. The details are of course not black and white – and the more I learned about CCS, the more I saw a strong case for the technology but also questioned its viability.

First some background– CCS or carbon capture and storage is a technology that seeks to either retrofit machinery onto exiting power plants, or to be built into new "CCS-ready" power plants that prevent CO2 from being released. The extra sub-systems capture and compress the CO2 and then transport it to a long-term storage location, usually a subterranean geologic formation called a saline aquifer that will (in theory) hold the CO2 for an eternity, until it eventually mineralises creating stable, solid formations.

That's the layman's research I did before starting work at the Global CCS Institute. I started to to question the viability of CCS when I learned the following (in chronological order)

The CCS subsystem that is attached to power plants has a large degree of "parasitic load" meaning that it actually uses a lot of extra energy to run, reducing the efficiency and making electricity more expensive than it was before.

The other name for CCS is CCUS– the "U" stands for use. In North America especially, much of the CO2 harvested from power plants is sold on to oil field companies to pump into exhausted wells so they can get the last dregs of petroleum out.

Even the preparation for a CCS project to be implemented can take years, particularly because of the time and effort required to find a storage site.

There were few examples of large, successful CCS plants anywhere (at the time I started) becuase the technology was really difficult, expensive and no one was spending the required amount of money to make it happen.

Although these were some issues that tested my supoprt for the technology– there were some other important things I learned about CCS that tilted the scale in the other direction:

CCS is not just about capturing from power plants– cements, fertiliser and other industries are massive emitters of CO2- and systems to capture these emissions should be in place regardless of our energy mix

Although I'm a strong supporter of renewable energy– the pragmatic truth is that it feels hypocritical to tell developing countries to only use more expensive renewable energy when rich developed countries still haven't weened themselves off fossil fuel.

Many developing countries have a strong case that making electricity accessible (regardless of the technology) must be their top priority, and if fossil fuels are the way they are going to do this then it is certainly better for the climate if its done with CCS.

There are some really interesting ideas on the fringes of CCS that intrigue my techie side - BioEnergy with CCS (BECCS) is the idea of growing dedicated biofuel crops, combusting them for energy and then capturing the CO2. This process could lead to negative emissions, as the plants capture the CO2 from the air.

Is CCS a Cleanleap technology? A Cleanleap is about jumping ahead in technological development with minimal environmental damage– I think there may be some of this happening in BECCS or industrial CO2 capture – but perhaps not in the power industry. All low-emission energy technologies have their issues (rare earths for solar, bird deaths and noise for wind) but it's CCS, hydropower and nuclear that introduce the greatest potential environmental damage.

Another criticism of CCS is that it acts as a shield for companies contuing to exploit fossil fuel – a bit of CCS related lip service provides a pretext for continuing to mine and burn coal. It could be argued that even if the technological basis for CCS is sound, the benefit is outweighed by its misuse from PR flacks looking to shield big corporate miners, power companies and even governments from the bad news about burning fossil fuel and climate change. Even this is a complex stance to take however as there does not seem to be a lot of evidence that these purely PR exercises are driving the continued uptake of fossil fuels – instead it seems to come down to simple arithmetic, available reserves (which are massive for coal and reasonably well-distributed) and price.

So with all these things in mind should we still be pushing ahead with CCS? My answer is a nuanced "yes" – because the climate change issue is so big and complex and many of best potential solutions are in the early stages of implementation. But as the industry changes over time and if CCS continues to lag in delivery it may find itself out of the mix. Unless technologies like renewables are filling the gap, to me that would seem like a very bad result.